On page 258 under the Y-wing weapons it list the proton torpedo as:

Forward mounted Proton torpedo launchers (2) (fire arc forward; damage 8; crit 2; range [short]; breach 6, blast 6, guided 2, limited ammo 8, linked 1, slow-firing 1)

Am I reading this right, it has 4 launchers with a total ammo of 16. If this is right then a player could spend the 1 hard point to link all launches so it has one launcher with link 3

You might want to post your question in the Edge of the Empire main forum. This is the old beta forum. The book has since been released so there isn't a reason for others to go here.